Microsoft® Visual Basic® Scripting Edition
FileExists Method Scripting Run-Time Reference
Version 3
Description
Returns True if a specified file exists; False if it does not.
Syntax
object.FileExists(filespec)
The FileExists method syntax has these parts:

Part Description
object Required. Always the name of a FileSystemObject.
filespec Required. The name of the file whose existence is to be determined. A complete path specification (either absolute or relative) must be provided if the file isn't expected to exist in the current folder.

Remarks
The following example illustrates use of the FileExists method:
Function ReportFileStatus(filespec)
Dim fso, msg
Set fso = CreateObject("Scripting.FileSystemObject")
If (fso.FileExists(filespec)) Then
msg = filespec & " exists."
Else
msg = filespec & " doesn't exist."
End If
ReportFileStatus = msg
End Function

marvanFSO придётся таскать с собой, т.к. инсталится он только при установке OutlookЧтобы убедиться в обратном, советую посмотреть состав директории I386: scrrun.dl_ там пристутствует в обязательном порядке.